Multiple element cyclonic separator



Jan.v6, 1959 N. M. MCGRANE 2,867,290 v MULTIPLE ELEMENT CYCLONIC SEPARATOR I Original Filed March .'ILS, 1953 .W/QMAA/ ./l. MCGIQANE,

INVENTOA MULTIPLE ELEMENT CYCLONC SEPARATOR Norman M. Mcrane, Long Beach, Calif., assignor to Western Precipitation Corporation, Los Angeles, Calif., a corporation of California Original application March 16, 1953, Serial No. 342,653, no vv Patent No. 2,768,744, dated October 30, 1956. ggrgtgg and this application July 9, 1956, Serial No.

2 Claims. (Cl. 18S-83) l`his invention relates to means for treating gaseous fluids for the separation of suspended material therefrom, and more particularly relates to improvements in a device of this character incorporating multiple Cyclonic elements.

The present application is a division of my co-pending application Serial No. 342,653, filed March 16, 1953, for Multiple Element Cyclonic Separator, now Patent No. 2,768,744, granted October 30, 1956.

It is well known that a single Cyclonic element of relative small diameter is more etiicient than a single large diameter element and will remove from a stream of gas suspended particles too small for separation in the larger diameter element. It follows that a plurality of small diameter cyclonic elements used to treat a large gas stream should have the same higher level of efficiency. Certain practical diiiiculties, however, commo-nly prevent attainment of the theoretical efciency.

One problem is to obtain substantially uniform effective pressure differentials across all the various cyclonic separator elements with substantially the same inlet pressures at all the individual elements. An important-object of `the invention, therefore, is to provide a separator incorporating a plurality of small diameter Cyclonic elements arranged to obtain uniform distribution of the incoming gas stream among the separator elements with maximum `possible eflciency in each element.

Broadly described, the invention attains its objects by lemploying a housing enclosing a plurality of cyclonic elements in the form of separating tubes positioned in an inlet chamber opposite a front gas inlet of the housing with the successively rearward tubes in the chamber at successively lower levels along the path of the inflowing gas. The transverse top wall of the inlet chamber drops progressively in the direction of entering gas flow to lower levels at the successive separating tubes. Each sep- :arating tube has an axial outlet tube extending out of the fseparating tube through this transverse top wall into an 'outlet chamber that communicates with the gas outlet of the housing. The transverse top wall of the inlet chamber may either slope uniformly downward or step down- -ward by stages to the levels of the successive tubes. This transverse wall not only separates the gas inlet chamber from the gas outlet chamber, but also preferably supports the outlet tubes and the upper end of' the separating tubes. In addition, the transverse top wall cooperates with the separating tubes to form a portion of the involute inlet .into the upper ends of the separating tubes.

To equalize pressures at the inlets of all the separating tubes requires minimizing resistance to gas tlow through the inlet chamber so that the gas may move freely and Vequally to all the separating tubes. A feature of the invention to-this respect is that minimum resistance to Vgas ow through the inlet chamber is achieved by arranging the separating tubes in rows extending in the direction of entering gas flow and spaced apart laterally to form between two rows of tubes a rearwardly extending gas passage. There may be several such passages. A further feature is the provision of involute inlets for 2,867 ,299 Patented Jan. e, 195s the separating tubes with the involute walls of the inlet extending into one of the rearwardly extending gas passages to guide gas into the tubes. Also a feature of a preferred embodiment of the invention is the provision of straight side walls for at least a part of the length of the gas passage to minimize turbulence and eddying therein.

A second transverse wall is provided at a point below the first transverse wall, the second wall serving to divide the inlet chamber from the lower portion of the housing which becomes a hopper space into which the lower ends of all lof the separating tubes open. The dust or other particles separated from the gas stream are discharged through the open ends of the tubes into this hopper space. In the present invention this second or lower transverse wall forms a floor to the inlet chamber and is disposed at the same level as the bottom of the involute inlet to the last or lowest tube in the row. Any material that settles out of the gas stream and drops onto this second transverse wall is swept rearwardly by the gas stream and carried into the inlet of the last tube in the row. After entering this last tube, the particles pass through the tube into the hopper space.

In this description, the gas inlet side of the housing is referred to as the front side and the opposite side is referred to as the back side, for convenient reference with respect to the direction of gas flow. These and any other directional terms, as for example upper-or lower I and the like, are used for descriptive purposes and are Fig. 1 is a side elevation of a cyclonic separator constructed according to my invention, with a portion of the side wall of the housing broken away;

Fig. 2 is a fragmentary front elevation of the separator with a portion of the front wall of the housing broken away; and

Fig. 3 is a horizontal section on the line 3 3 of Fig. l, but rotated counter-clockwise.

It will be apparent to one skilled in the art that the invention may be embodied in structures of other configuration than shown. In Figs. 1-3 a rectangular housing, generally designated at 10, is mounted on an angle iron framework that includes four legs 11. The outer I, housing may be made of metal sheets forming two spaced side walls 12., a front wall 13, a rear'wall 14, and a top wall 15. The sheets forming these walls may be inter connected and re-'enforced by horizontal angles 19 and Ztl at the top and bottom of the housing respectively, and by the vertical angles 21 at the corners.

The housing 10 has a rectangular gas inlet opening 24 in the front wall 13 surrounded by an angle iron frame 25 to which suitable ductwork (not shown in the drawing) may be connected. A similar rectangular gas outlet opening 26 in top wall Y15 -is surrounded by an angle iron frame 27. Outlet 26 may exhaust directly to the atmosphere as shown or to any suitable type of gas duct (not shown in the drawing) that may be connected ,to flange 27. A feature of the invention is that the gas inlet 24 and the gas outlet 26 may alternatively be at the' same level and in alignment with each other, the gasoutlet then being in rear wall 14. This alternative construction is shown in my co-pending application Serial No. 342,653 referred to above.

Inside of housing 10, a transverse wall 30, which may be made of steel plate, separates the space adjacent gas inlet 24 from the space adjacent gas outlet 26. The space below and to the left of transverse wall 30 is in communication with inlet 24 and is designated as inlet chamber 31. The vspace above and tothe right of transversie wall communicates with outletk26 and is designated as outlet chamber 32. Wall 30 slopes downwardly and Yrearwardly with respectv to the direction ot' gas tlow entering throughinlet 24-and extendsentirelyzacross.the

housing between sidewalls 1-2. yThis transverse wallis. commonlyreferredto as a tube sheetf.- .Asecond:trains` verse wall l islocated below `the first.mentioned.trans-k verse wall, vand .is also commonly referred to l as a f-tube sheet. Wall 35 forms 'the bottom` of inlet :chamber 31V and separatesthisinlet chamber from'the Vspace 36 Venclosed within -the housing f. and'-below -the wall. This latter space is the hopper-space. `The upper portion of the V hopper space- Sois *boundedv by =frontend .rear walls 13 and 1.42 and side walls -l2;=-andV the ...space extends downwardlyffinto hopper 3,7which tapers toward the bottom1tof1ead 4toa suitable dust discharge valve meegaan motion to the gas stream as it enters each tube to form adownwardly moving vortex. The longitudinal rows of separating tubes are spaced apart laterally to form rearwardly extending gas passages that permit the in- `flowing gas to reach therearward tubes in each row.

In the particular construction shown, the four longitudiiial rows. bcseparating tubes; 4.4; are. .arranged in rtwo 1 pairs of.rows, Vthe two rowsrof each pair .being spaced passage 48 in whole. vorgin part rto Supply only the tubes 40-which may discharge-the-jdust into any'suitable Atype v of receptacle'for duct, not shown infthe drawing.

.'Loweritransverse-wall35 iswpre'ferably horizontal, as shown, ,for practical reasonsybutitis `within the scopeV of rnywinventiony .t'o incline the f walldownwardly and rearwardly :to some degree asillustratedfin myv jsaid 'copending application. l

, vA plurality ofcyclonic dustl separating elements .in the form of separating tubes 44 are located within housing 10, with their upper ends located Withinjand :in `communicationfwith inlet chamber 31.` Each `separating tube has a conicallys'tapered flowerfportion which-is open at-theV bottom, thef'opening'inv the lowerfendzof the tube=being in communication'with-:hopper space. Tubes -44'` are shown.aslfhavingjtheir laxes .vertical or :substantially so, and-'thisiis .a-usual. and'preferred arrangement; but the invention is not necessarily limited to a vertical position forthe tubeax'es.4 The :separating tubes are .opennat their upper/.tends Lto receive- #gascand the particles isuspen'dedf therein from-linl'etichamber 31; .a'ndthe' tubes lare arranged in: a plura'lity of -r'ows which:extendsfacross the Vinlet chambe'rfro'm front'fto' rear,`-`paral1el ;to v the direction' of flow in the gas stream'entering'.throtighinlet y24.".:The'se rowsare hereinafter referred to-fas longitudinal la'nd eachincludes thetour tubes aligned along-faneaxis 44a in Fig. 3. The successively rearward tubes in each row areJ positioned `at 'successivelyflower-levels; as may-be seen particularly fromFig. ll. rl'heupper :ends4 of' the separating tubes in ythelfrontfof thefinletchamber .adj'acentinlet 24 arenearfthetoplevel ofgas inlet opening 24 while the upper ends offthe-rear-most tubes vare near the bottom llevel 'of'"-the vgas 'inlet opening. 'With this arrangement; the successive tube -inlets intercept successively lower Yfractions-'of the owing' gas stream, as vwill bey further explained. Y Y

' The slopeof transverse wall`1'2t0 is'deterininedffby 'the downward" spacingfof 'the v'tubes' with'l respect to -each other since the transverse wall extends lacross Vand closes v the open upper end'of leach-separating {tube-44. -Each ofithe Vseparating' tubes has ash'ort-coaxialfoutlet-tube 45 which extends upwardly'through'transverse wall '30 to communicate with outlet "charn'benl The 'cleaned gas leaves the'se'paratingtub'es throughoutlet tubes`` 45 and' enters outletchamberi'from Whichitrijs ydischarged through outlet opening' 26.

In the particular formjillustratedin"t11e`drawings,there are sixteenv separating `ftube/s `14,4`inthe inlet chamber, arranged in four parallel' "longitudinalrows extending from front to rear ofthe housing. The tubes are'alsoconveniently arrangedin four transverserows extending from side to side of the housing.i T he' upperends ofthe separating tubes are fastenedto 'andfsupp'ortedrom' II-.lbe sheet 30. Transverse wall 35 engages'eachgone .'offthe tubes some point below'the `upper.transvrerse wallj'the position of 4engagement lalong the "length of `the.' tube depending upon the position. ofthetubeinits longitudinally extending row. Y

The "upper 'ends of jthe "separating 'tubes .are constructed andarrang'ed'toform agas inlet that7 imparts a' spinningv in a single row. In this arrangement one wall of the i gas passage-wouldordinarily be adjacent aside 'wall i2 ofthe housing.'V

. Each/ .of the separating tubes 44, has a forwardly facing gasinletoi the .involute type,.asindicated.at in 2. This inlet .is .shown ,in-.section in Eig. 3. .for the .second i tubes in=each of .thevlongitudinally extending rows. .Each

involute inlet is formed byv a vertically,extending,-hori zontally curved, spiralV ywall51y that blends .tangentially into the. uppery end of. the cylindrical wall of .the separating tube. ylheinvolute inlet. passage is further.. defined by a portion vof vtransverse wall 30 which provides aV topv to .theinvolute passage. .The bottom. of eaclrfinvolute passageisdened-byan arcuate wall 52,.shown in Fig. 3.. `Asrnay be seen =in-Fi g.4 3, the forward edgesfofA the` spiral Walls 51 of each pairfof separating tubes located l at opposite sides of a longitudinal gas passage 48, meet at the middle-'of the gas passage to.:divideequa lly be tween'the twoseparating'tubes.gthe.,iniowing .gas at the level of the .involute passage.

. ,Each ofthe longtudinalfgas. passages 48, ator below theglevel of the vinlet to the'secorrd vtubes-.ofeach longioutside -ofy -the separating tubes.

tudinal trow, -is. provided with. a fpair. ofi'sidejwalls 54.

each-formed by a flat,fsmooth-plate=1mounted on the s These platesyextend rearwardly fromabout the center ofthe front tube :to

I the involute inlets of the successiveV tubesy ineach row.

The side walls 54 of the gas passagesAy may-be made from a `single-sheet or theymay'conveniently be made asshown, in ,sections ofvvarying lengthgin the directionY of .gas ow,v each section having a height equal tofthe vertical .dimension of .theinvolute inlet 5.0. Such wall sections :abut each.. other along. their top -and bottomA edges to eliminate openings .through whichthe gas 'could pass to leave a .passage 48 `so ithat the several sections are, in effect, aisolid wall. With four:..tubes;in -a-.lofngiside wall 54, as mayV beJseen: by. reference tFig..1.prNo plate i is required Vat the. involute. inlet of 1 the rst v:..tube offeach rowfbecausefthel'spiralfwalls SL'of thetwoffront tubesfextend iforwardly to :substantially: fithe center -lineof the-tubes 1in the :frontrowfandwith tubes-4 4, '.pro-

vide the only means required '.tO'deneJthegas passage atthisflevel. For each Y.successi-ve :.tubeinthe direction of Vgas flow, the distance of. 'gasfflowina passage :48;is-

successively longer. Gas lpassages 4S-are closed. iatrthe bottom by-lower transverse wall35 which ,engagesfthe holes tolpermit' theinsertion of-arodor airflancey atV bottom edges of side walls A54.' Thus .there is .defined Va longitudinal gas passage.=extending between twovadjacent -but laterally spaced 'longitudinal vrows of tubes,

variousgjpontsV around and just-tabove walllSS. for the purpose of' dislodgingllafnv "solid material ftlratlrnay-k'r be accumulated lon top of transverse wall 35. In the present construction, pipe nipples 56 are mounted on the walls of the housing at these holes, the nipples normally closing the rodding holes but being removable to open them. Similar nipples 57 are provided to close rodding holes in rear wall 14 which are located in a position to provide access to the top surface of upper transverse wall 30.

Having described the construction of a preferred embodiment of my invention in a multiple tube cyclonic separator, its operation will be briefly described. The particle-laden gas stream enters the housing through gas inlet 24 and is substantially equally divided into smaller streams, two in this case, that flow rearwardly through longitudinal gas passages 48. A certain amount of the heavier particles suspended in the gas stream may drop out of the gas stream as it passes through inlet chamber 31. These heavier particles settle onto the horizontal tube sheet 35 which forms the bottom wall lof each gas passage 48. When the dust concentration is high, there may be a considerable amount of material which accumulates on this transverse wall. The gas stream flowing through passages 48 tends to move such settled material along the horizontal tube sheet and eventually sweeps it into the inlets of the rearmost tubes where it is separated from the gas stream in the same manner as the other particles of dust.

The particle-laden gas entering the involute inlet 50 of each of the separating tubes 44 forms a vortex around the outlet tubes 45. The gas stream moves downwardly within the separating tube 44 in a spiral and then turns and spirals upwardly in a smaller inner vortex to enter 'the lower end of the outlet tube which is concentric of the separating tube. The particles of suspended material are separatedby centrifugal action during the spiral movement and are carried by the downward spiral through the open lower end of the separating tube into hopper space 36. The separated particles collect in hopper 37 and are removed as often as may be required through dust valve 40. The clean gas from the several outlet tubes 45 enters outlet chamber 32 and then leaves the housing by way of outlet 26.

The fact that the incoming gas stream reaches all of the separating tubes with substantially the same degree of freedom, and the further fact that all of the separating tubes 44 are of equal length, as are also the outlet tubes 45, makes for uniformity of distribution of the gas stream among the several separating tubes.

My description in detail of a presently preferred embodiment of the invention may suggest to those skilled in the art various changes, substitutions, or other departures from the above disclosure that properly lie within the spirit and scope of the appended claims. For example, it may be desirable to use a stepped upper transverse wall 30 as shown in my said co-pending application instead of the uniformly sloping wall illustrated herein.

Hence it is to be understood that the foregoing description is considered as being illustrative of, rather than limitative upon, the invention as defined by the appended claims.

I claim:

1. Apparatus for separating suspended particles from a stream of gas by centrifugal action, comprising: a housing having a gas inlet and a gas outlet; a pair of rows of separating tubes inside the housing, each tube having a forwardly facing involute inlet near the top and the rows each containing a plurality of tubes, each row extending generally in the direction of ow of the gas stream entering the housing and having the tubes in that row at levels progressively lower in said direction of gas ow, and the rows being spaced transversely of the direction of said gas llow to allow the gas to pass between forward tubes to reach and enter rearward tubes of the rows; an upper transverse wall within the housing cooperating with the housing to deline an inlet chamber and an outlet chamber communicating respectively with the gas inlet and the gas outlet of the housing, said wall extending rearwardly and downwardly across successively lower levels of the path of gas flowing into the housing through said inlet and closing the upper end of said separating tubes and the involute inlets; an outlet tube concentric of each separating tube and extending upwardly through said transverse wall; and a lower transverse wall within the housing cooperating with the housing to dene the bottom wall of said inlet chamber and a hopper space beneath said second wall, said lower wall engaging the tubes in each of said rows at`dii`rerent relative positions along the length of the tubes and being at the level of the bottom of the gas inlet of the last tube of each row.

2. Apparatus as in claim 1 which also includes vertical wall members adjacent the sides of the laterally spaced rows of separating tubes, said vertical wall members extending rearwardly from the forward separating tubes to the inlets of the other separating tubes and in cooperation with the two transverse walls forming a gas passage for rearward flow of gas from said housing inlet to the tube inlets rearward of the forward separating tubes.

References Cited in the file of this patent UNITED STATES PATENTS 2,327,691 Allardice Aug. 24, 1943 2,433,774 Madely Dec. 30, 1947 2,439,850 Heller Apr. 20, 1948 2,533,991 Blomquist et al. Dec. 12, 1950 FOREIGN PATENTS 473,484 Great Britain Oct. ll, 1937' 379,989 Italy Apr. 15, 1940 497,568 Canada Nov. 10, 1953 

